Flexible polyurethane foam-forming composition and flexible polyurethane foam

Abstract

A flexible polyurethane foam-forming composition including: a polyisocyanate (A); a castor oil-based polyol (B1); a polyether polyol (B2) including a polyether polyol having two hydroxyl groups; and a foaming agent (C).

Description

Composition for forming flexible polyurethane foam and flexible polyurethane foam

[0001] This disclosure relates to compositions for forming flexible polyurethane foam and flexible polyurethane foam.

[0002] Polyurethane foam is used in a wide range of applications, including household goods, automotive interior materials, clothing, sports and leisure goods, medical materials, and civil engineering and construction materials. Therefore, the properties required of polyurethane foam are also diverse.

[0003] For example, Patent Document 1 discloses a method for producing a flexible foamed synthetic resin by foaming a polyhydroxy compound and an organic polyisocyanate in the presence of water and additives as a catalyst, foam stabilizer, and foaming agent. It states that this production method has the effect of preventing compression set and deterioration of curability due to water foaming and additives, and obtaining a low-density, low-hardness foam.

[0004] Japanese Patent Application Publication No. 6-336514

[0005] However, conventional flexible polyurethane foams, including the flexible foamed synthetic resin described in Patent Document 1, have considerable room for improvement in their elongation properties. Therefore, the present disclosure aims to provide a flexible polyurethane foam having excellent elongation properties. The present disclosure also aims to provide a composition capable of forming such a flexible polyurethane foam.

[0006] This disclosure provides, for example, the inventions described in [1] to

[10] below.

[0007] [1] A composition for forming a flexible polyurethane foam, comprising a polyisocyanate (A), a castor oil-based polyol (B1), a polyether polyol (B2) containing a polyether polyol having two hydroxyl groups, and a blowing agent (C).

[0008] According to the composition of [1], a flexible polyurethane foam having excellent elongation properties can be produced. The elongation of the flexible polyurethane foam, which is a reaction product of the composition of [1], measured in accordance with JIS K6400-5:2012, is, for example, 1.1 to 1.5 times that of the comparative flexible polyurethane foam described later. The elongation of the flexible polyurethane foam produced by the composition of [1], measured in accordance with JIS K6400-5:2012, is, for example, 110 to 132%.

[0009] Furthermore, the flexible polyurethane foam, which is a reactant of composition [1], has a moderate hardness. Specifically, the F hardness, measured using a rubber hardness tester (Asuka-F type), is, for example, 58 to 91 points.

[0010] Furthermore, the flexible polyurethane foam, which is a reaction product of composition [1], has excellent breathability. Specifically, the air permeability measured in accordance with JIS K6400-7:2012 is, for example, 2.7 to 19.8 cm. ３ / cm ２ It is per second.

[0011] Furthermore, the flexible polyurethane foam, which is a reactant of composition [1], exhibits excellent moldability during molding. Specifically, it is possible to mold a polyurethane foam in which phenomena such as collapse, where the flexible polyurethane foam sinks significantly after reaching its maximum height, and shrinkage of the generated flexible polyurethane foam immediately after foaming or after curing, are reduced to a degree that does not pose practical problems.

[0012] [2] (B2) contains a polyether having a different number of hydroxyl groups than 2, which is an impurity during the synthesis of the polyether polyol having 2 hydroxyl groups, and the average number of hydroxyl groups FB2 of the polyether polyol having 2 hydroxyl groups and the polyether having a different number of hydroxyl groups than 2, calculated by the following formula (1), is 1.6 to 1.95, the composition according to [1].

[0013] [In the formula, OHV represents the total hydroxyl value (mgKOH / g) of (B2) calculated in accordance with Method B of JIS K 1557-1:2007, and IHD represents the total unsaturation (meq / g) of (B2) calculated in accordance with JIS K 1557-3:2007, respectively.]]

[0014] [3] The composition according to [2], wherein the average number of hydroxyl groups FB2 is 1.65 to 1.9.

[0015] The flexible polyurethane foam which is a reaction product of the composition of [2] or [3] has more excellent elongation properties.

[0016] [4] The composition according to any one of [1] to [3], comprising at least one crosslinking agent (B3) selected from the group consisting of glycerin, ethylene glycol, diethanolamine and triethanolamine.

[0017] By incorporating (B3) described in [4], the flexible polyurethane foam which is a reaction product of the composition of [4] becomes more excellent in F hardness and air permeability.

[0018] [5] The composition according to any one of [1] to [4], wherein the composition may optionally contain an active hydrogen-containing compound other than (B1) and (B2), and among the components contained in the composition, the average number of active hydrogen groups F of (B1), (B2) and the active hydrogen-containing compound Ｈ is 2.1 to 2.45.

[0019] [6] The composition according to any one of [1] to [5], wherein the composition may optionally contain an active hydrogen-containing compound other than (B1) and (B2), and the functional group index F calculated by the following formula (2) Ｈ＋ＮＣＯ is 2.1 to 2.45.

[0020] [In the formula, F ＮＣＯ is the average number of isocyanate groups of (A), F Ｈ is the average number of active hydrogen groups of (B1), (B2) and the active hydrogen-containing compound, C ＮＣＯ is the proportion of the amount of (A) relative to the total amount of (A), (B1), (B2) and the active hydrogen-containing compound in the composition, C ＨThis indicates the ratio of the amounts of (B1), (B2), and the active hydrogen-containing compound to the total amount of (A), (B1), (B2), and the active hydrogen-containing compound in the above composition.

[0021] The flexible polyurethane foam, which is a reactant of composition [5] or [6], will have better elongation properties.

[0022] [7] A composition according to any one of [1] to [6], comprising a hindered phenol antioxidant (D).

[0023] By including (D) described in [7], the flexible polyurethane foam, which is a reaction product of the composition in [7], has improved long-term stability, especially long-term stability under high-temperature conditions.

[0024] [8] The above composition may contain active hydrogen-containing compounds other than (B1) and (B2), and is a two-component composition according to any one of [1] to [7], wherein (B1), (B2) and the above active hydrogen-containing compounds are separated from (A).

[0025] In composition [8], the reactive components of (A) are separated, making storage easier, and the two-component structure also makes it easier to blend them in the required stoichiometric ratio. "Two-component structure" means that (A), (B1), (B2), and the active hydrogen-containing compound are stored separately (for example, in separate containers). Even when divided into three or more parts (for example, in three or more containers), i.e., in the case of "multi-component structure," the reactive components are divided into at least two parts, so it is included in "two-component structure."

[0026] A flexible polyurethane foam which is a reaction product of any of the compositions described in [9], [1], to [8].

[0027]

[10] The soft polyurethane foam described in [9], with an F hardness of 30 to 95 points.

[0028] The flexible polyurethane foams of [9] and

[10] have sufficient elongation properties, moderate hardness, and excellent breathability, as described above.

[0029] According to the present disclosure, a flexible polyurethane foam having excellent elongation properties can be provided, and a composition capable of forming the flexible polyurethane foam can be provided.

[0030] Hereinafter, embodiments of the present disclosure will be described in detail. In the present disclosure, a numerical range indicated using "~" denotes a range that includes the numerical values described before and after "~" as the minimum value and the maximum value, respectively. Unless explicitly stated otherwise, the units of the numerical values described before and after "~" are the same. Further, each configuration and parameter can be arbitrarily combined, and the individually described upper limit values and lower limit values can be arbitrarily combined. Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more kinds.

[0031] The composition for forming a flexible polyurethane foam according to the present disclosure comprises a polyisocyanate (A), a castor oil-based polyol (B1), a polyether polyol having 2 hydroxyl groups (b2 ｐｒｉ ), a polyether polyol (B2) containing the above, and a blowing agent (C).

[0032] Flexible polyurethane foam refers to a reversibly deformable foam that has an open-cell structure and exhibits high air permeability [see, for example, Gunter Oertel, "Polyurethane Handbook" (1985 edition), Hanser Publisher (Germany), pages 161 to 233; Iwata Keiji, "Polyurethane Resin Handbook" (first edition 1987), Nikkan Kogyo Shimbun, pages 150 to 221].[

[0033] The physical properties of flexible polyurethane foam vary depending on the chemical structures of polyols, isocyanates and the like used in the production thereof, the blending amount of the blowing agent, chemical factors such as the isocyanate index, the cell structure and the like, so it is difficult to specifically define them. In general, the density (which can be measured as an apparent density; the same applies hereinafter) is 10 to 100 kg / m ３(JIS K 6401), compressive strength (ILD 25%) is in the range of 2 to 80 kgf (20 to 800 N) (JIS K 6401) [see, for example, Gunter Oertel, "Polyurethane Handbook" (1985 edition), Hanser Publishing GmbH (Germany), pp. 184-191 and 212-218; Keiji Iwata, "Polyurethane Resin Handbook" (1987 first edition), Nikkan Kogyo Shimbun, pp. 160-166 and 186-191].

[0034] Furthermore, semi-rigid polyurethane foam, while having a higher foam density and compressive strength than flexible polyurethane foam, possesses an open-cell structure similar to flexible polyurethane foam, exhibiting high breathability and reversible deformation. Since the raw materials used in its manufacture, such as polyols and isocyanates, are the same as those for flexible polyurethane foam, it is generally classified as flexible polyurethane foam [see, for example, Gunter Oertel, "Polyurethane Handbook" (1985 edition), Hanser Publishing (Germany), pp. 223-233; and Keiji Iwata, "Polyurethane Resin Handbook" (1987 first edition), Nikkan Kogyo Shimbun, pp. 211-221]. The physical properties of semi-rigid polyurethane foam are not particularly limited, but generally, its density is 40-800 kg / m³. ３ , 25% compressive strength is 0.1–2 kgf / cm² ２ The range is (9.8 to 200 kPa).

[0035] In contrast, rigid polyurethane foam has a highly cross-linked closed-cell structure and is a foam that cannot be reversibly deformed, possessing properties completely different from those of flexible and semi-rigid polyurethane foam [see, for example, Gunter Oertel, "Polyurethane Handbook" (1985 edition), Hanser Publishing (Germany), pp. 234-313; Keiji Iwata, "Polyurethane Resin Handbook" (1987 first edition), Nikkan Kogyo Shimbun, pp. 224-283]. The properties of rigid foam are not particularly limited, but generally, the density is 20-100 kg / m³. ３ , compressive strength of 0.5 to 10 kgf / cm２ The range is (50 to 1000 kPa).

[0036] In this disclosure, "flexible polyurethane foam" includes not only flexible polyurethane foam having the above-described properties, but also semi-rigid polyurethane foam having the above-described properties.

[0037] Polyisocyanate (A) can be any compound having two or more isocyanate groups. From the viewpoint of high reactivity of the isocyanate groups and good curing properties, diphenylmethane diisocyanates (hereinafter referred to as MDI), such as 4,4'-diphenylmethane diisocyanate (hereinafter referred to as 4,4'-MDI), 2,4'-diphenylmethane diisocyanate (hereinafter referred to as 2,4'-MDI), 2,2'-diphenylmethane diisocyanate (hereinafter referred to as 2,2'-MDI), polymethylene polyphenylene polyisocyanate (hereinafter referred to as P-MDI), and tolylene diisocyanate (hereinafter referred to as TDI) may be used as the isocyanate source. In this disclosure, various modified materials such as MDI, TDI, mixtures of MDI and P-MDI, mixtures of TDI and P-MDI, urethane modified materials, carbodiimide modified materials, urea modified materials, allophanate modified materials, isocyanurate modified materials, and biuret modified materials may also be used. Among these, a mixture of MDI and P-MDI may be used from the viewpoint of enabling the molding of flexible polyurethane foam over a wide density range.

[0038] The MDI content of polyisocyanate (A) relative to the total amount of MDI and P-MDI may be in the range of 50 to 85% by mass, from the viewpoint of easily obtaining polyurethane foam with high durability and elongation properties. If the MDI content exceeds 85% by mass, the storage stability of the obtained polyisocyanate composition at low temperatures and the durability of the obtained foam may decrease. On the other hand, if it is less than 50% by mass, the elongation of the polyurethane foam decreases as the crosslinking density increases, making it difficult to obtain sufficient foam strength.

[0039] Furthermore, the sum of the content of 2,2'-MDI and the content of 2,4'-MDI relative to the total amount of MDI (hereinafter referred to as the isomer content) may be 10 to 50% by mass, and may also be 10 to 30% by mass from the viewpoint of high reactivity and shortening the molding cycle.

[0040] If the content of 2,2'-MDI and 2,4'-MDI relative to the total amount of MDI is less than 10% by mass, the storage stability of the resulting polyisocyanate composition at low temperatures may be impaired, and it may be necessary to keep the isocyanate storage area, piping, and foam molding machine constantly heated. In addition, the molding stability of the polyurethane foam may be impaired, and foam collapse during foaming may occur. On the other hand, if it exceeds 50% by mass, the reactivity decreases, the molding cycle is extended, the degree of foam closure increases, and problems such as shrinkage after molding may occur.

[0041] The isomer ratios, such as the content of the 2,4-isomer and the 2,6-isomer relative to the total amount of TDI, are not particularly limited.

[0042] The TDI content relative to the total amount of TDI and P-MDI may be 20 to 80% by mass.

[0043] The polyisocyanate (A) content in the flexible polyurethane foam forming composition according to this disclosure may be 30 to 85% by mass or 50 to 75% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0044] Examples of castor oil-based polyols (B1) include castor oil (refined castor oil, semi-refined castor oil, unrefined castor oil, etc.), hydrogenated castor oil obtained by adding hydrogen to castor oil, and other castor oil-modified polyols, and castor oil itself may also be used. Castor oil is a triester of fatty acids and glycerol, and approximately 90 mol% of the total constituent fatty acids in castor oil is ricinoleic acid. Therefore, castor oil usually contains a triester of three molecules of ricinoleic acid and one molecule of glycerol, as well as a triester of two molecules of ricinoleic acid and one molecule of castor oil constituent fatty acid other than ricinoleic acid and one molecule of glycerol. Examples of castor oil constituent fatty acids other than ricinoleic acid include palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. The number of hydroxyl groups in the castor oil-based polyol (B1) can be 2 to 3, and may be 2.2 to 2.8, or 2.5 to 2.9. Because the composition for forming flexible polyurethane foam according to this disclosure contains castor oil-based polyol (B1), it is possible to form a flexible polyurethane foam with high heat resistance. The castor oil-based polyol (B1) may be one type or two or more types.

[0045] The weight-average molecular weight of the castor oil-based polyol (B1), determined by gel filtration chromatography (GPC), may be 500 to 1500, 700 to 1200, or 850 to 1050, from the viewpoint of making it easier to obtain a flexible polyurethane foam with better hardness.

[0046] The content of castor oil-based polyol (B1) in the flexible polyurethane foam forming composition according to this disclosure may be 10 to 50% by mass or 20 to 40% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0047] Polyether polyol (B2) contains polyether polyol (b2) which has 2 hydroxyl groups. ｐｒｉExamples of polyoxyethylene polyoxypropylene polyols include polyoxyethylene polyoxypropylene polyol (hereinafter also referred to as "PPG"), polyoxypropylene polyols, and polytetramethylene glycol. From the viewpoint of high molding stability of polyurethane foam, polyoxyethylene polyoxypropylene polyol may also be used.

[0048] In this disclosure, the number of functional groups such as the number of hydroxyl groups in a compound means a value determined based on the chemical structural formula of the compound. For example, a polyether polyol (b2) has two hydroxyl groups. ｐｒｉ ) is b2 ｐｒｉ Based on the chemical formula (i.e., the chemical formula of the target product free of impurities), this means that the number of hydroxyl groups is 2. The number of functional groups, such as the number of hydroxyl groups, can be determined, for example, by known methods, for example, １３ This can be determined by identifying the chemical structure of the target compound using methods such as C-NMR, ESI-TOF / MS, and MALDI-TOF / MS. Furthermore, polyether polyols (b2 ｐｒｉ The number of hydroxyl groups in ) is, for example, １３ The chemical structure of the initiator can be determined by identifying it using methods such as C-NMR, ESI-TOF / MS, and MALDI-TOF / MS. Furthermore, the number of functional groups, such as the number of hydroxyl groups in a compound, can also be determined by identifying its chemical structure based on the synthesis process of the compound. For example, a polyether polyol produced by repeatedly ring-opening and adding alkylene oxide using an initiator with two active hydrogen groups can be determined to have two hydroxyl groups.

[0049] Furthermore, as mentioned above, polyether polyols (b2) have two hydroxyl groups. ｐｒｉ) may be the main product (the most abundant product on a molar basis) in the reaction between an initiator having two active hydrogen groups and an alkylene oxide. Examples of initiators having two active hydrogen groups include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, etc. Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, etc.

[0050] In this disclosure, polyether polyol (B2) is defined as polyether polyol (b2) ｐｒｉ ) May contain polyethers with 0 or 1 hydroxyl group, which are impurities or by-products during synthesis. For example, polyether polyol (B2) may contain polyether polyol (b2) with 2 hydroxyl groups. ｐｒｉ ) may consist only of a polyether polyol (b2) having 2 hydroxyl groups. ｐｒｉ ) and polyethers (b2) that have a different number of hydroxyl groups than 2, which are impurities during synthesis. ｂｙ ) may also contain. In the latter case, polyether polyol (B2) is a polyether polyol (b2) having 2 hydroxyl groups. ｐｒｉ ) and polyethers with a different number of hydroxyl groups (b2 ｂｙ ) may consist only of a polyether polyol (b2) having 2 hydroxyl groups. ｐｒｉ ), or a mixture of a polyether polyol having 1 hydroxyl group and a polyether having 0 hydroxyl groups.

[0051] Polyether polyols (B2) containing polyether polyols with two hydroxyl groups are, for example, reaction products of an initiator with two active hydrogen groups and an alkylene oxide. In the reaction of an initiator with two active hydrogen groups and an alkylene oxide, the above polyether polyol with two hydroxyl groups is synthesized, as well as polyether polyols with a different number of hydroxyl groups (b2) ｂｙIn some cases, a by-product may be generated and remain as an impurity. For example, the above reaction can be carried out in the presence of a basic catalyst, in which case the alkylene oxide is deprotonated and ring-opened in the presence of the basic catalyst to be converted to an alkenyl oxide anion, and the alkylene oxide is repeatedly ring-opened and added using the alkenyl oxide anion as an initiator, thereby generating a polyether monool having one ethylenically unsaturated bond (derived from the above alkenyl oxide anion) as an impurity. For the mechanism of such impurity generation, see, for example, "Susumu Sato, Masahiro Saito, and Kingo Miura. "Excess ratio and unsaturated bond in alkylene oxide addition polymerization." Journal of Industrial Chemistry 69.3 (1966): 501-505.", "Ryozo Motoyama. "Production of polyalkylene oxides and their uses." Journal of Synthetic Organic Chemistry, Japan 23.3 (1965): 267-272." Furthermore, for example, in the reaction of an initiator with two active hydrogen groups and an alkylene oxide in the presence of a basic catalyst, the alkoxide anion obtained by repeated ring-opening addition of the alkylene oxide to the initiator undergoes a chain transfer reaction with the alkylene oxide, converting the terminal alkoxide group of the alkoxide anion to an alkenyl group with the same number of carbon atoms. This can result in the formation of a polyether monool having one ethylenically unsaturated bond (derived from the alkenyl group) and / or a polyether having two ethylenically unsaturated bonds (derived from the alkenyl group) and zero hydroxyl groups as an impurity. For the mechanism of such impurity formation, see, for example, "Ryozo Motoyama. "Production of Polyalkylene Oxides and Their Applications." Journal of Synthetic Organic Chemistry, Japan 23.3 (1965): 267-272." As described above, polyethers with a different number of hydroxyl groups (b2 ｂｙ ) can be a polyether having 0 or 1 hydroxyl group, or a polyether having 1 hydroxyl group. Also, a polyether (b2) with a different number of hydroxyl groups as an impurity. ｂｙ) is likely to be generated when propylene oxide and / or butylene oxide are used as the alkylene oxide, and is particularly likely to be generated when propylene oxide is used as the alkylene oxide. Furthermore, polyether (b2) is produced as a by-product impurity. ｂｙ ) is included in the reaction product of an initiator with two active hydrogen groups and an alkylene oxide.

[0052] Polyether polyol (b2) has 2 hydroxyl groups. ｐｒｉ ) and the polyether polyol (b2 ｐｒｉ ) Polyethers (b2) that have a different number of hydroxyl groups than 2, which are impurities during synthesis. ｂｙ The number-average molecular weight of the mixture may be 500 to 10,000, 1,000 to 8,000, or 2,000 to 6,000, from the viewpoint of making it easier to obtain a flexible polyurethane foam with better hardness. If the number-average molecular weight is below the lower limit, the resulting flexible polyurethane foam tends to lack flexibility, and if it exceeds the upper limit, the hardness of the flexible polyurethane foam tends to decrease.

[0053] The content of polyether polyol (B2) in the flexible polyurethane foam forming composition according to this disclosure may be 5.0 to 50% by mass or 20 to 40% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0054] Polyether polyol (B2) has 2 hydroxyl groups, which is polyether polyol (b2) ｐｒｉ ) and the polyether polyol (b2 ｐｒｉ ) Polyethers (b2) that have a different number of hydroxyl groups than 2, which are impurities during synthesis. ｂｙ The average hydroxyl group number FB2 calculated by the above formula (1) may be 1.6 to 1.95, 1.65 to 1.9, 1.7 to 1.85, or 1.75 to 1.8, from the viewpoint of further improving the elongation of the flexible polyurethane foam.

[0055] Castor oil-based polyol (B1) and polyether polyol (b2) having 2 hydroxyl groups ｐｒｉ ) can be polyadded with polyisocyanate (A) to form polyurethane.

[0056] The flexible polyurethane foam forming composition according to this disclosure may contain at least one crosslinking agent (B3) selected from the group consisting of glycerin, ethylene glycol, diethanolamine, and triethanolamine. The crosslinking agent can further improve the hardness of the flexible polyurethane foam and the curability during molding of the flexible polyurethane foam.

[0057] The content of the crosslinking agent (B3) in the flexible polyurethane foam forming composition according to this disclosure may be 0.1 to 5% by mass or 0.5 to 4% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0058] The composition for forming flexible polyurethane foam according to this disclosure may contain a connecting agent (B4) from the viewpoint of improving the air permeability, durability, etc., of the foam. The connecting agent (B4) may contain a polyether polyol having four hydroxyl groups and a polyoxyalkylene chain made of a copolymer of oxyethylene and oxypropylene. The number average molecular weight of the polyether polyol may be 3,000 to 8,000. The weight average molecular weight of the polyether polyol determined by GPC may be 5,000 to 11,000 or 7,000 to 9,000 from the viewpoint of making it easier to obtain a flexible polyurethane foam with better hardness. The oxyethylene units in the polyether polyol may be 60 to 90% by mass or 60 to 80% by mass from the viewpoint of easily improving the durability of the foam. By setting the oxyethylene units in the polyether polyol to 60 to 90% by mass, the durability of the foam can be improved. Furthermore, from the viewpoint of storage stability at low temperatures, the copolymer made of oxyethylene and oxypropylene may be a random copolymer.

[0059] The above-mentioned connecting agent (B4) may be a reaction product of an initiator having 4 active hydrogen groups and an alkylene oxide, and may contain polyethers having a different number of hydroxyl groups, which are impurities during the synthesis of the polyether polyol having 4 hydroxyl groups. In this case, the average number of hydroxyl groups FB4 of the polyether polyol having 4 hydroxyl groups and the polyethers having a different number of hydroxyl groups, calculated by the following formula (3), may be 3.0 to 4.0.

[0060] [In the formula, OHV represents the total hydroxyl value (mgKOH / g) of the connecting agent (B4) calculated according to Method B of JIS K 1557-1:2007, and IHD represents the total degree of unsaturation (meq / g) of the connecting agent (B4) calculated according to JIS K 1557-3:2007.]

[0061] The content of the communicating agent (B4) in the flexible polyurethane foam forming composition according to this disclosure may be 0.1 to 5% by mass or 0.5 to 4% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0062] The flexible polyurethane foam forming composition according to this disclosure may contain polyols other than those described above. Examples of such polyols include polyester polyols. Examples of polyester polyols include a polycondensation type polyester polyol consisting of adipic acid and a diol, and a lactone-based polyester polyol such as polycaprolactone polyol.

[0063] The total polyol content in the flexible polyurethane foam forming composition according to this disclosure may be 30 to 90% by mass or 50 to 70% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0064] Examples of the foaming agent (C) include water; low-boiling point organic compounds such as cyclopentane and isopentane; a combination of water and a low-boiling point organic compound; or, from the viewpoint that the weight of the low-boiling point organic compound decreases due to volatilization and the amount added is less stable compared to water, water alone may also be used. Water has two active hydrogen groups that react with isocyanate groups, and when these active hydrogen groups react with the isocyanate groups, a high-hardness urea group is formed and carbon dioxide is generated, thereby causing foaming.

[0065] Furthermore, air, nitrogen gas, liquefied carbon dioxide, etc., can be used as the foaming agent (C). In the production of flexible polyurethane foam (i.e., the reaction product of the flexible polyurethane foam forming composition according to this disclosure), air, nitrogen gas, liquefied carbon dioxide, etc., can be mixed and dissolved into the flexible polyurethane foam forming composition using a gas loading device to cause foaming.

[0066] The water content as a foaming agent (C) in the flexible polyurethane foam forming composition according to this disclosure may be 0.1 to 10% by mass based on the total mass of the flexible polyurethane foam forming composition. ３ In this case, the content may be 0.1 to 5% by mass or 0.5 to 2% by mass. By keeping it below these upper limits, foaming can be stably produced, and by keeping it above these lower limits, the density of the foam can be sufficiently increased.

[0067] The composition for forming flexible polyurethane foam according to this disclosure may contain a hindered phenol antioxidant (D). The hindered phenol antioxidant (D) can impart long-term stability to the flexible polyurethane foam in high-temperature environments. The hindered phenol antioxidant (D) may be one type or two or more types.

[0068] As the hindered phenol antioxidant (D), from the viewpoint of being liquid at room temperature and having good miscibility with other components, it may be an ester of 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionic acid with an alkyl alcohol having 7 to 9 carbon atoms and a branched structure (Irganox 1135 from BASF Japan), or an ester of 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionic acid with an alkyl alcohol having 18 carbon atoms (Irganox 1076 from BASF Japan).

[0069] The content of the hindered phenol-based antioxidant (D) in the flexible polyurethane foam forming composition according to this disclosure may be 0.01 to 5% by mass or 0.1 to 1% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0070] The flexible polyurethane foam forming composition relating to this disclosure may contain a catalyst (E). As catalyst (E), known urethane catalysts (E) can be used, such as amine catalysts like triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N,N',N',N''-pentamethyldiethylenetriamine, bis-(2-dimethylaminoethyl) ether, triethylenediamine, 1,8-diazabicyclo[5.4.0]undecene-7, 1,2-dimethylimidazole, dimethylethanolamine, N,N-dimethyl-N-hexanolamine, N,N-dimethylethanolamine, and N,N-diethylethanolamine; organic salts thereof; organometallic compounds such as stanus octoate and zinc naphthenate. From the viewpoint of minimizing the risk of deterioration over time such as heat resistance and water resistance, it may be an amine catalyst or triethylenediamine. Catalyst (E) may be one type or two or more types.

[0071] The content of catalyst (E) in the flexible polyurethane foam forming composition according to this disclosure may be 0.05 to 3% by mass or 0.1 to 1.5% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0072] The flexible polyurethane foam forming composition according to this disclosure may contain a foam stabilizer (F). The foam stabilizer (F) may be a known surfactant, and from the viewpoint of having a high effect in making bubbles uniform and stabilizing, it may be a silicone-based surfactant (i.e., a silicone-based foam stabilizer). Examples of silicone-based foam stabilizers include TF1365, SZ-1327, SZ-1325, SZ-1336, SZ-3601 from Dow Toray, Y-10366J, L-5309J from Momentive, and B-8724LF2, B-8715LF2 from Evonik. The foam stabilizer (F) may be one type or two or more types. Silicone-based foam stabilizers usually have polysiloxane chains.

[0073] The content of the foam stabilizer (F) in the flexible polyurethane foam forming composition according to this disclosure may be 0.1 to 3% by mass or 0.3 to 1.5% by mass, based on the total mass of the flexible polyurethane foam forming composition.

[0074] The flexible polyurethane foam forming composition according to this disclosure may contain, in addition to the components described above, fillers such as calcium carbonate and barium sulfate, and other known additives and auxiliary agents such as flame retardants, plasticizers, colorants, and antifungal agents. The total content of these other components in the flexible polyurethane foam forming composition according to this disclosure may be 0 to 30% by mass, 0 to 10% by mass, or 0 to 5% by mass, based on the total mass of the flexible polyurethane foam forming composition according to this disclosure.

[0075] The composition for forming flexible polyurethane foam according to this disclosure may contain active hydrogen-containing compounds other than castor oil-based polyol (B1) and polyether polyol (B2). From the viewpoint of further improving the elongation of the flexible polyurethane foam, the average number of active hydrogen groups of the active hydrogen-containing compounds other than castor oil-based polyol (B1) and polyether polyol (B2) among the components contained in the composition for forming flexible polyurethane foam according to this disclosure may be 2.1 to 2.45, 2.15 to 2.42, or 2.18 to 2.4. In this disclosure, an active hydrogen-containing compound is a compound having active hydrogen that reacts with an isocyanate group, and typically has active hydrogen groups such as OH, NH, and SH, which react with the isocyanate group to form a urethane bond, a urea bond, and a thiourethane bond, respectively. In this specification, unless otherwise specified, an active hydrogen-containing compound includes castor oil-based polyol (B1) and polyether polyol (B2).

[0076] Here, examples of active hydrogen-containing compounds other than castor oil-based polyols (B1) and polyether polyols (B2) include other polyols other than castor oil-based polyols (B1) and polyether polyols (B2) that have two hydroxyl groups, as well as water. Note that the hydroxyl groups in castor oil-based polyols (B1), polyether polyols (B2) that have two hydroxyl groups, and other polyols contain active hydrogen groups. Average number of active hydrogen groups F Ｈ In calculating the average number of active hydrogen groups F of polyether polyols and polyethers containing polyethers, which are impurities generated during the synthesis of said polyether polyols (for example, polyether polyol (B2)), ｐｏｌｙｅｔｈｅｒ This is calculated using the following formula (4).

[0077] [In the formula, OHV is the total hydroxyl value of the polyether calculated in accordance with Method B of JIS K 1557-1:2007 (mgKOH / g), IHD is the degree of unsaturation of the polyether calculated in accordance with JIS K 1557-3:2007 (meq / g), FB ｐｏｌｙｅｔｈｅｒｐｏｌｙｏｌThe numbers indicate the number of hydroxyl groups in the above polyether polyols.

[0078] Furthermore, from the viewpoint of further improving the elongation of the flexible polyurethane foam, the functional group index F calculated by the above formula (2) is used. Ｈ＋ＮＣＯ This may be 2.1 to 2.45, or 2.2 to 2.45 or 2.25 to 2.44.

[0079] Functional group index F Ｈ＋ＮＣＯ In the calculation of the average number of active hydrogen groups F of the polyether polyol and the polyether component containing the polyether which is an impurity during the synthesis of the polyether polyol (for example, polyether polyol (B2)), ｐｏｌｙｅｔｈｅｒ This is calculated using the formula (4) described above.

[0080] The composition for forming flexible polyurethane foam according to this disclosure may be a two-component composition in which the active hydrogen-containing compound is separated from the polyisocyanate (A). For example, the active hydrogen-containing compound and the polyisocyanate (A) may be contained in separate containers. In this case, for example, the hindered phenol antioxidant (D) may be contained in the same container as the active hydrogen-containing compound.

[0081] The flexible polyurethane foam according to this disclosure is a reaction product of a polyisocyanate (A), a castor oil-based polyol (B1), a polyether polyol (B2) containing a polyether polyol with two hydroxyl groups, and a blowing agent (C). The flexible polyurethane foam according to this disclosure may be a reaction product of the above-described flexible polyurethane foam forming composition.

[0082] The flexible polyurethane foam according to this disclosure has excellent elongation properties. Here, "having excellent elongation properties" of the flexible polyurethane foam means that the elongation of the flexible polyurethane foam, as measured in accordance with JIS K6400-5:2012, is greater than that of the comparative flexible polyurethane foam described later. For example, if the elongation of the former is 1.05 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times, or 1.5 times or more greater than the elongation of the latter, the flexible polyurethane foam according to this disclosure can be said to have excellent elongation properties. The comparative flexible polyurethane foam is a reaction product of polyisocyanate (A), blowing agent (C), and polyol, wherein the polyol does not include a polyether polyol with 2 hydroxyl groups or a reaction product of an initiator with 2 active hydrogen groups and alkylene oxide. Specifically, any of the flexible polyurethane foams of Comparative Examples 1 to 3 described in the Examples described later can be cited.

[0083] Here, the elongation of the flexible polyurethane foam according to this disclosure, as measured in accordance with JIS K6400-5:2012, may be 100-150%, and may be 105-140% or 107-135%. On the other hand, the elongation of the comparative flexible polyurethane foam, as measured in accordance with JIS K6400-5:2012, is typically around 86-94%.

[0084] The reason why the flexible polyurethane foam relating to this disclosure has excellent elongation properties is not entirely clear, but it is because it is a polyether polyol (b2) with 2 hydroxyl groups. ｐｒｉ It is believed that the polyaddition of (A) with polyisocyanate (A) reduces the crosslinking density of the above-mentioned flexible polyurethane foam, thereby improving its elongation properties.

[0085] The F hardness of the flexible polyurethane foam according to this disclosure may be 30 to 95, and may be 40 to 93 or 50 to 92. In this disclosure, F hardness means the value measured using a rubber hardness tester (Asuka-F type). F hardness can be improved, for example, by including a crosslinking agent in the composition for forming flexible polyurethane foam (more specifically, for example, an active hydrogen-containing compound separated from polyisocyanate (A) in the composition).

[0086] The bulk density of the flexible polyurethane foam relating to this disclosure is 100 to 130 kg / m³. ３ It could be 110-125 kg / m ３ Or 112-120 kg / m ３ This may also be the case. In this disclosure, bulk density is the apparent density (kg / m³) of the entire flexible polyurethane foam measured in accordance with JIS K-6400:2004. ３ This means that the weight (W) of a rectangular prism of flexible polyurethane foam (200 mm long x 200 mm wide x 10 mm thick) is measured, and then the volume (V) is determined from the length, width, and thickness of the rectangular prism, and the bulk density (ρ) is calculated.

[0087] The air permeability of the flexible polyurethane foam relating to this disclosure is 0.5 to 30 cm. ３ / cm ２ It can be per second, and 1 to 25 cm. ３ / cm ２ / second or 2-20cm ３ / cm ２ It may be per second. In this disclosure, the airflow rate means a value measured in accordance with JIS K6400-7:2012.

[0088] The flexible polyurethane foam according to this disclosure can be manufactured, for example, by thoroughly mixing a polyisocyanate (A), a castor oil-based polyol (B1), a polyether polyol (B2) containing a polyether polyol with two hydroxyl groups, and a blowing agent (C), and then reacting and foaming them.

[0089] Specifically, methods such as injecting a mixture of polyisocyanate (A), castor oil-based polyol (B1), polyether polyol containing a polyether polyol with two hydroxyl groups (B2), and a foaming agent (C) (hereinafter also referred to as "foaming stock") into a mold and then foaming and curing it to produce flexible polyurethane mold foam (hereinafter sometimes referred to as "flexible mold foam"), or supplying the foaming stock into a foaming container or continuously onto a belt conveyor and foaming it to produce flexible polyurethane slab foam (hereinafter sometimes referred to as "flexible slab foam") can be employed.

[0090] Polyisocyanate (A), castor oil-based polyol (B1), polyether polyol (B2) containing a polyether polyol with 2 hydroxyl groups, and blowing agent (C) may be mixed so as to have an isocyanate index of 70 to 140, or from the viewpoint of improving the molding cycle, they may be mixed so as to have an isocyanate index of 70 to 120. The isocyanate index is the percentage of the total number of isocyanate groups of polyisocyanate (A) to the total number of active hydrogen groups of the active hydrogen-containing compounds (total number of isocyanate groups / total number of active hydrogen groups × 100).

[0091] In the manufacture of flexible mold foam, the mold temperature when injecting the foaming liquid into the mold may typically be 30 to 80°C or 45 to 70°C. If the mold temperature when injecting the foaming liquid into the mold is below 30°C, it may lead to a decrease in the reaction rate and an extension of the production cycle. On the other hand, if it is above 80°C, the reaction between water and isocyanate may be excessively promoted compared to the reaction between polyol and isocyanate, which may cause the foam to collapse during the foaming process.

[0092] The curing time when foaming and hardening the foam concentrate can be 10 minutes or less, or even 7 minutes or less, considering the production cycle of a typical flexible mold foam.

[0093] When manufacturing flexible molded foam, the above components can be mixed using a high-pressure foaming machine, a low-pressure foaming machine, etc., as with ordinary flexible molded foam.

[0094] The polyisocyanate (A), castor oil-based polyol (B1), polyether polyol (B2) containing a polyether polyol with two hydroxyl groups, and the foaming agent (C) may be mixed immediately before foaming, as this allows for adjustment of the mixing ratio each time. The mixture (foaming concentrate) may be used immediately after mixing, or it may be stored and used as needed.

[0095] Furthermore, the mixing method may be dynamic mixing, which is performed in the mixing chamber of the foaming machine's machine head, or static mixing, which is performed in the liquid delivery piping, or both may be used in combination. Static mixing is often used for mixing gaseous components such as physical foaming agents with liquid components, while dynamic mixing is often used for mixing components that can be stably stored as liquids. The foaming device may be a high-pressure foaming device that does not require solvent cleaning of the mixing section.

[0096] The mixture obtained by this mixing process is poured into a mold, allowed to foam and harden, and then demolded. To facilitate demolding, a mold release agent may be applied to the mold beforehand. Any mold release agent commonly used in the molding process can be used. Examples of mold release agents include T-626 (manufactured by Chukyo Oil & Fat Co., Ltd.).

[0097] The demolded flexible polyurethane foam can be used as is, but the cell membrane of the foam may be broken under compression or reduced pressure by known methods to stabilize the appearance and dimensions of the product thereafter.

[0098] Because the flexible polyurethane foam relating to this disclosure has the excellent performance described above, it may be used in household goods, automotive interior materials, clothing, sports and leisure goods, medical materials, etc.

[0099] The present disclosure will be further described in detail below with reference to examples.

[0100] [Formation of Flexible Polyurethane Foam] [Raw Materials, etc.] In the formation of flexible polyurethane foam, unless otherwise specified, the raw materials, etc. described below were used. Polyisocyanate 1: A polyisocyanate (manufactured by Tosoh Corporation, "CEF-538") containing 70% by mass of diphenylmethane diisocyanate (MDI) and 24% by mass of polymethylene polyphenylene polyisocyanate (polymeric MDI, P-MDI). The total content of 2,4'-MDI and 2,2'-MDI (isomer content) is 17.7% by mass based on the total amount of MDI. The content of MDI relative to the total amount of MDI and P-MDI is approximately 74% by mass. The isocyanate group content is 28.8% by mass. The average number of isocyanate groups is 2.52. Castor oil-based polyol 1: A castor oil-based polyol (manufactured by Giant Agro, "H-300") made from refined castor oil with an average number of hydroxyl groups of 2.7, a hydroxyl value of 160 (mg KOH / g), and a weight-average molecular weight of 945 determined by GPC. Polyether polyol 1: A polyoxyethylene polyoxypropylene polyol (manufactured by Kagaku Chemical Co., Ltd., "Puranol D-4021") with a nominal number of hydroxyl groups of 2. The hydroxyl value of polyether polyol 1 as a whole (including polyether, which is an impurity during the synthesis of polyoxyethylene polyoxypropylene polyol. The number of hydroxyl groups determined based on the chemical structural formula of the polyoxyethylene polyoxypropylene polyol is 2) is 28 (mg KOH / g), and the number-average molecular weight is 4000. Polyether polyol 2: Polyoxyethylene polyoxypropylene polyol with a nominal number of hydroxyl groups = 3 (AGC Corporation, "Exenol EL-823"). The hydroxyl value of polyether polyol 2 as a whole (including polyether, which is an impurity during the synthesis of polyoxyethylene polyoxypropylene polyol. The number of hydroxyl groups determined based on the chemical structural formula of the polyoxyethylene polyoxypropylene polyol is 3) is 33 (mgKOH / g), and the number average molecular weight is 5000. Polyether polyol 3: Polyoxyethylene polyoxypropylene polyol with a nominal number of hydroxyl groups = 4 and containing 80% by mass of oxyethylene units (Tosoh Corporation, "NEF-024").The hydroxyl value of polyether polyol 3 as a whole (including polyether, which is an impurity during the synthesis of polyoxyethylene polyoxypropylene polyol; the number of hydroxyl groups determined based on the chemical structural formula of the polyoxyethylene polyoxypropylene polyol is 4) is 28 (mgKOH / g), and the weight-average molecular weight determined by GPC is 8000. Glycerin 1: Manufactured by NOF Corporation, "Glycerin DG" Diethanolamine 1: Manufactured by Nippon Shokubai Co., Ltd., diethanolamine Amine Catalyst 1: Amine catalyst (manufactured by Tosoh Corporation, "TEDA-L33") Amine Catalyst 2: Amine catalyst (manufactured by Tosoh Corporation, "TOYOCAT-ET") Silicone-based foam stabilizer 1: Silicone-based foam stabilizer (manufactured by Dow Toray, "TF1365") Silicone-based foam stabilizer 2: Silicone-based foam stabilizer (manufactured by Momentive, "L5309J") Antioxidant: Hindered phenol-based antioxidant (manufactured by BASF Japan, "Irganox 1135") Mold release agent 1: Manufactured by Chukyo Oils Co., Ltd., "T-626".

[0101] Table 1 shows the results of determining the degree of unsaturation (meq / g) of polyether polyols 1 to 3 in accordance with JIS K 1557-3:2007. As shown in Table 1, since none of polyether polyols 1 to 3 had a degree of unsaturation of 0, it was indicated that polyether polyols 1 to 3 contain polyether, which is an impurity from the synthesis of polyether polyols.

[0102] As described above, the number of hydroxyl groups in polyether polyols 1 to 3 is 2, 3, and 4, respectively. Also, as described above, the total hydroxyl values ​​of polyether polyols 1 to 3 are 28, 33, and 28 (mgKOH / g), respectively. Based on these facts, the above hydroxyl values, and the above degree of unsaturation, the average number of hydroxyl groups of the polyether polyols and the polyether impurities calculated by formula (1) is shown in Table 1 below.

[0103]

[0104] [Preparation of Compositions Containing Active Hydrogen Compounds] Each component listed in "Compositions Containing Active Hydrogen Compounds" in Table 2 below was weighed into a polypropylene cup (1 L) in the amounts (unit: parts by mass) listed in Table 2. The mixtures were then mixed at 1400 revolutions per minute for 20 minutes at room temperature (25°C) using a small high-speed stirrer (PRIMIX, manufactured by Primix Corporation) to obtain compositions P-1 to P-6 (Examples 1 to 3 and Comparative Examples 1 to 3, respectively) containing active hydrogen compounds.

[0105] [Formation of Flexible Polyurethane Foam] Compositions P-1 to P-6 containing an active hydrogen-containing compound were mixed with polyisocyanate 1 as shown in Table 2 in the amount shown in Table 2. The mixture was then mixed for 7 seconds at 7000 revolutions per minute using a small high-speed stirrer (PRIMIX, Inc.) to prepare the foaming stock solutions for Examples 1 to 3 and Comparative Examples 1 to 3. Immediately after preparing the foaming stock solutions, they were injected into a mold to foam the flexible polyurethane foam. The foaming was carried out under the following conditions. Release agent 1 was used as a release agent. The flexible polyurethane foam was then removed from the mold. <Foaming Conditions> Mold temperature: 55-65°C Mold shape: 300 mm x 300 mm x 10 mm Mold material: Aluminum Cure time: 6 minutes

[0106] In Table 2, the "Isocyanate Index" refers to the percentage of the total number of isocyanate groups of polyisocyanate (A) relative to the total number of active hydrogen groups of castor oil-based polyol 1, polyether polyols 1-3, glycerin 1, diethanolamine 1, and water in the above-mentioned foaming stock solution (total number of isocyanate groups / total number of active hydrogen groups × 100). The number of active hydrogen groups of polyether polyols 1-3 is based on the "average number of hydroxyl groups of polyether polyols and impurity polyethers" described in Table 1 above.

[0107] [Evaluation of Flexible Polyurethane Foam] The flexible polyurethane foams formed in Examples 1-3 and Comparative Examples 1-3 were evaluated based on the following evaluation method, and the results are shown in Table 2.

[0108] [Bulk Density] The apparent density (kg / m³) of the entire flexible polyurethane foam, measured in accordance with JIS K-6400:2004. ３) is measured and this is used to determine the bulk density (kg / m³). ３ Specifically, the weight (W) of a rectangular prism of flexible polyurethane foam (200 mm long x 200 mm wide x 10 mm thick) was measured, and then the volume (V) was determined from the length, width, and thickness of the rectangular prism, and the bulk density (ρ) was calculated.

[0109] [F Hardness] The F hardness of the soft polyurethane foam was measured using a rubber hardness tester (Asuka-F type).

[0110] [Air permeability] Air permeability of flexible polyurethane foam (cm³) in accordance with JIS K6400-7:2012 ３ / cm ２ The rate (per second) was measured.

[0111] [Elongation] The elongation (%) of the flexible polyurethane foam was measured in accordance with JIS K6400-5:2012.

[0112] [Moldability] The moldability of the flexible polyurethane foam was evaluated. Specifically, a "○" was given if the polyurethane foam could be molded without phenomena such as collapse (where the flexible polyurethane foam sinks significantly after reaching its maximum height) or shrinkage of the generated flexible polyurethane foam immediately after foaming or after curing.

[0113]

[0114] As shown in Table 2, the elongation of the flexible polyurethane foams in Examples 1 to 3, which contained a castor oil-based polyol and a polyether polyol (polyether polyol 1) containing a polyether polyol with two hydroxyl groups, was greater than that of Comparative Examples 1 to 3, which did not contain a polyether polyol (polyether polyol 1) containing a polyether polyol with two hydroxyl groups. Therefore, it was shown that a composition for forming flexible polyurethane foam containing a castor oil-based polyol and a polyether polyol containing a polyether polyol with two hydroxyl groups can form a flexible polyurethane foam with excellent elongation properties.

Claims

1. A composition for forming flexible polyurethane foam, comprising a polyisocyanate (A), a castor oil-based polyol (B1), a polyether polyol (B2) containing a polyether polyol with two hydroxyl groups, and a blowing agent (C).

2. Said (B2) comprises a polyether having a number of hydroxyl groups different from 2, which is an impurity generated during synthesis of a polyether polyol having 2 hydroxyl groups, and the average hydroxyl number FB2 of said polyether polyol having 2 hydroxyl groups and said polyether having a number of hydroxyl groups different from 2, which is calculated by the following formula (1), is 1.6 to 1.

95. The composition according to claim 1. [In the formula, OHV represents the total hydroxyl value (mgKOH / g) of (B2) calculated in accordance with Method B of JIS K 1557-1:2007, and IHD represents the total degree of unsaturation (meq / g) of (B2) calculated in accordance with JIS K 1557-3:2007, respectively.]] 3. The composition according to claim 2, wherein the average number of hydroxyl groups FB2 is 1.65 to 1.

9.

4. The composition according to claim 1, comprising at least one crosslinking agent (B3) selected from the group consisting of glycerin, ethylene glycol, diethanolamine, and triethanolamine.

5. The composition may also contain active hydrogen-containing compounds other than (B1) and (B2), and among the components contained in the composition, (B1), (B2) and the average number of active hydrogen groups of the active hydrogen-containing compounds F Ｈ The composition according to claim 1, wherein the ratio is 2.1 to 2.

45.

6. The composition may also contain active hydrogen-containing compounds other than (B1) and (B2), and the functional group index F calculated by the following formula (2) Ｈ＋ＮＣＯ The composition according to claim 1, wherein the ratio is 2.1 to 2.

45. [In the formula, F ＮＣＯ (A) is the average number of isocyanate groups, F Ｈ (B1), (B2), and the average number of active hydrogen groups in the active hydrogen-containing compound, C ＮＣＯ This is the ratio of the amount of (A) to the total amount of (A), (B1), (B2) and the active hydrogen-containing compound in the composition, C Ｈ This indicates the ratio of the amounts of (B1), (B2), and the active hydrogen-containing compound to the total amount of (A), (B1), (B2), and the active hydrogen-containing compound in the composition.

7. The composition according to claim 1, comprising a hindered phenol antioxidant (D).

8. The composition may contain active hydrogen-containing compounds other than (B1) and (B2), and the composition according to claim 1 is a two-component composition in which (B1), (B2) and the active hydrogen-containing compounds are separated from (A).

9. A flexible polyurethane foam which is a reaction product of the composition according to any one of claims 1 to 8.

10. The flexible polyurethane foam according to claim 9, wherein the F hardness is 30 to 95 points.

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